POS1114 CHARACTERISTICS OF DIFFICULT TO TREAT AXIAL SPONDYLOARTHRITIS: A COMPARATIVE ANALYSIS
Authors: T. Delepine, E. Cailliau, P. Philippe, X. Deprez, N. Taisne, E. Houvenagel, T. Pascart, R. M. Flipo, J. G. Letarouilly
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The concept of difficult-to-treat rheumatoid arthritis (D2T RA) has recently emerged. It is defined by the persistence of disease activity and the failure of at least 2 b/tsDMARDs of 2 different mechanisms of action (MoA) [1]. In this definition, the period during which the treatments have failed is not included. The D2T concept has not yet been applied with consensus in axial spondyloarthritis (axSpA). <h3>Objectives</h3> To study the characteristics of patients with D2T axSpA to better identify the potential causes of treatment failure. The second objective was to study a sub-group of D2T axSpA patients with a predefined time criteria. <h3>Methods</h3> A multicentric retrospective longitudinal study was performed in secondary and tertiary centers. axSpA diagnosis was based on ASAS criteria. Patients were followed up from January 2016 to December 2021. Patients starting a b/tsDMARDs with a minimum of 2-year follow-up were included. D2T axSpA patients were defined as patients who received more than 2 b/tsDMARDs with different MoA among b/tsDMARD available. These patients were compared to non-difficult-to-treat axSpA patients (nD2T axSpA) using statistical tests. Very D2T axSpA patients were defined as patients who received at least 2 b/tsDMARDs in less than 2 years during the time of follow-up. <h3>Results</h3> 311 patients were included, 88 were D2T axSpA and 223 nD2T axSpA. Baseline characteristics are presented in the Table 1. No statistical difference was found between the 2 groups regarding main comorbidities, including fibromyalgia and depression. Among the D2T patients, 76 (86%) had presented a primary or secondary inefficacy from 2 drugs with different MoA and 12 (14%) presented a contraindication to TNFinhibitor or IL17 inhibitor (multiple sclerosis, inflammatory bowel diseases, recurrent uveitis, solid cancer less than 5 years old). Seven patients were categorized as very D2T axSpA. When compared to the rest of the D2T axSpA group, no significant difference was observed. <h3>Conclusion</h3> Significant differences were found between the characteristics of patients D2T axSpA and nD2T axSpA, which were the smoking status, axSpA duration, presence of arthritis, history of uveitis and baseline BASDAI. Limitations exist about applying the EULAR D2T RA definition to axSpA. The inclusion of a time should also be considered. <h3>Reference</h3> [1]Nagy G, Roodenrijs NM, Welsing PM, et al. EULAR definition of difficult-to-treat rheumatoid arthritis. Ann Rheum Dis 2021;80:31–5. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Thibaut DELEPINE: None declared, Emeline Cailliau: None declared, Peggy Philippe Speakers bureau: Abbvie, MSD, Fresenius, Pfizer, UCB Pharma, Novartis, Xavier Deprez Speakers bureau: Pfizer, UCB, Abbvie, Novartis, MSD, NICOLAS TAISNE: None declared, Eric Houvenagel: None declared, Tristan Pascart Speakers bureau: Novartis, Abbvie, Pfizer, René-Marc Flipo Speakers bureau: Novartis, Lilly, Abbvie, Pfizer, MSD, Jean-Guillaume Letarouilly Speakers bureau: Amgen, Abbvie, Biogen, BMS, Janssen, MSD, Novartis. , Consultant of: Abbvie, Grant/research support from: Pfizer.